Lens module with electrostrictive member for driving lenes

ABSTRACT

An exemplary lens module includes a first lens, a second lens and an electrostrictive member. An optical axis of the second lens is aligned with that of the first lens. The electrostrictive member defines a through hole therein for facilitating light passing through, and is sandwiched between the first lens and the second lens. A thickness direction of the electrostrictive member is parallel to optical axes of the first lens and second lens. The electrostrictive member is capable of deforming in the thickness direction thereof when an electric current with an intensity is applied thereto, and capable of returning back to its undeformed state when the electric current is removed, whereby a space between the first and second lenses is adjusted, and at least one of the first lens and second lens is moved.

BACKGROUND

1. Technical Field

The present invention relates to lens modules, and particularly, to alens module having a lens driving mechanism therein.

2. Description of Related Art

With ongoing developments of microcircuitry and multimedia technology,camera modules, including, for example, still camera modules and digitalcamera modules, are now in widespread use and are being combined withvarious electronic devices. These camera modules are usually required tohave autofocus and zoom function.

Lens modules and image sensors are key components in camera modules. Atypical lens module includes a lens assembly and a lens drivingmechanism. The lens driving mechanism can be, e.g., a step motorconfigured for driving the lens assembly to move relative to the imagesensor, or driving a single lens of the lens assembly to move, therebyachieving the autofocus or zoom function of the camera module. However,a typical step motor is heavy and bulky, and consumes a substantialamount of power, especially relative to the amount of power that can bestored in a typical battery system of a camera or an electronic device.

Therefore, there is room for improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present lens module can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present lens module.Moreover, in the drawings, like reference numerals designatecorresponding parts throughout the several views.

FIG. 1 is a schematic view of a lens module in accordance with a firstexemplary embodiment, the lens module including an electrostrictivemember sandwiched between lenses.

FIG. 2 is a schematic view showing a deformation of the electrostrictivemember of FIG. 1, wherein a lens position and a focus point of theentire lens module are correspondingly changed.

FIG. 3 is an isometric view of a lens module in accordance with a secondexemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present lens module will now be describedin detail below and with reference to the drawings.

Referring to FIG. 1, an exemplary lens module 10 in accordance with afirst exemplary embodiment, is shown. The lens module 10 includes afirst lens 21, a second lens 22 and an electrostrictive member 30sandwiched between the first lens 21 and the second lens 22. In presentexemplary embodiment, the first lens 21, the second lens 22 and theelectrostrictive member 30 are generally ring-shaped.

The first lens 21 has a central optical portion 210 and a peripheralportion 211 surrounding the central optical portion 210. The second lens22 has a central optical portion 220 and a peripheral portion 221surrounding the central optical portion 220. An optical axis of thefirst lens 21 is aligned with that of the second lens 22 (see dash linein FIGS. 1 and 2).

The electrostrictive member 30 is made from deformable materials, suchas an artificial muscle material. The artificial muscle material may be,e.g., ferroelectric polymers or dielectric elastomers. Such artificialmuscle materials are capable of deforming in a direction when anelectric current with an intensity is applied thereto, and capable ofreturning back to its undeformed shape when the electric current isremoved. A thickness direction of the electrostrictive member 30 isparallel to optical axes of the first lens 21 and the second lens 22. Inthe present exemplary embodiment, the electrostrictive member 30 isdeformable in the thickness direction thereof. The electrostrictivemember 30 has a first surface 301 and a second surface 302 on oppositesides in the thickness direction. The first surface 301 is adhered tothe peripheral portion 211 of the first lens 21. The second surface 302is adhered to the peripheral portion 221 of the second lens 22.

A through hole 31 is defined in a center of the electrostrictive member30, for facilitating light passing through. A central axis of thethrough hole 31 is aligned with the optical axes of the first and secondlenses 21, 22. In an alternative exemplary embodiment, theelectrostrictive member 30 is transparent to light, and the through hole31 is omitted.

Referring to FIG. 2, a deformation of the electrostrictive member 30 isshown when a power supply 35 provides an electric current to theelectrostrictive member 30. The first surface 301 and the second surface302 are electrically connected to a positive electrode and a cathodeelectrode of the power supply 35, respectively. In the illustratedembodiment, when the electrostrictive member 30 deforms, only the secondlens 22 is moved. The broken lines in FIG. 2 show an original positionof the second lens 22 and an original focus point A of the entire lensmodule when the electrostrictive member 30 is in T1 thickness. When theelectrostrictive member 30 deforms from the T1 thickness to T2thickness, a space between the first lens 21 and the second lens 22 iscorrespondingly increased, and the focus point of the entire lens moduleis changed from A to B. Preferably, a control unit (not shown) isprovided to control an intensity of the electric current, such that thedeformation degree of the electrostrictive member 30 can be changed. Itis understood that, in an alternative exemplary embodiment, theelectrostrictive member 30 is capable of driving the first lens 21 andthe second lens 22 to move.

Referring to FIG. 3, a lens module 40 in accordance with a secondexemplary embodiment is shown. The lens module 40 includes a first lensarray 41, a second lens array 43 and an electrostrictive member 42sandwiched between the first lens array 41 and the second lens array 43.The first lens array 41, the second lens array 43 and theelectrostrictive member 42 are generally square-shaped. The first lensarray 41 includes a plurality of first lenses 410, the second lens array43 includes the same quantity of second lenses (not shown), and thefirst lenses 410 align with the respective second lenses. Theelectrostrictive member 42 can have a plurality of through hole (notshown) therein, for facilitating light passing through.

It is understood that the above-described exemplary embodiments areintended to illustrate rather than limit the invention. Variations maybe made to the exemplary embodiments without departing from the spiritof the invention. Accordingly, it is appropriate that the appendedclaims be construed broadly and in a manner consistent with the scope ofthe invention.

1. A lens module, comprising: a first lens a second lens, an opticalaxis of the second lens being aligned with that of the first lens; andan electrostrictive member defining a through hole therein forfacilitating light passing through, and being sandwiched between thefirst lens and the second lens, a thickness direction of theelectrostrictive member parallel to optical axes of the first lens andsecond lens, the electrostrictive member capable of deforming in thethickness direction thereof when an electric current with an intensityis applied thereto, and capable of returning back to its undeformedstate when the electric current is removed, whereby a space between thefirst and second lenses is adjusted, and at least one of the first andsecond lenses is moved.
 2. The lens module of claim 1, wherein theelectrostrictive member has a first surface and a second surface onopposite sides thereof, the first surface adhered to the first lens, thesecond surface adhered to the second lens.
 3. The lens module of claim2, wherein the first surface and the second surface are electricallyconnected to a positive electrode and a cathode electrode of a powersupply, respectively, thereby applying the electric current to theelectrostrictive member.
 4. The lens module of claim 3, wherein theelectrostrictive member deforms when the intensity of the electriccurrent is varied.
 5. The lens module of claim 1, wherein a central axisof the through hole, an optical axis of the first lens and an opticalaxis of the second lens are aligned with each other.
 6. The lens moduleof claim 1, wherein the electrostrictive member is made from adeformable material.
 7. The lens module of claim 6, wherein thedeformable material is an artificial muscle material.
 8. The lens moduleof claim 7, wherein the artificial muscle material is selected from agroup consisting of ferroelectric polymers and dielectric elastomers. 9.A lens module, comprising: a first lens; a second lens, an optical axisof the second lens being aligned with that of the first lens; anelectrostrictive member made from an artificial muscle material spacingthe first lens and the second lens, a thickness direction of theelectrostrictive member parallel to optical axes of the first lens andsecond lens, the electrostrictive member being deformable along thethickness direction thereof when an electric current is applied thereon,thereby driving at least one of the first and second lenses to move; anda power supply being electrically connected to the electrostrictivemember to provide the electric current to the electrostrictive member.10. The lens module of claim 9, wherein the electrostrictive member hasa first surface and a second surface on opposite sides thereof, thefirst surface adhered to the first lens, the second surface adhered tothe second lens.
 11. The lens module of claim 9, wherein theelectrostrictive member has a through hole defined therein, a centralaxis of the through hole being aligned with optical axes of the firstlens and second lens.
 12. The lens module of claim 9, wherein theartificial muscle material is selected from a group consisting offerroelectric polymers and dielectric elastomers.
 13. A lens module,comprising: a first lens array comprising a plurality of first lenses; asecond lens array comprising a plurality of second lenses, an opticalaxis of each second lens being aligned with that of a respective one ofthe first lenses; an electrostrictive member made from an artificialmuscle material spacing the first lens array and the second lens array,a thickness direction of the electrostrictive member parallel to opticalaxes of the first lenses and second lenses, the electrostrictive memberbeing deformable along the thickness direction thereof when an electriccurrent is applied thereon, thereby driving at least one of the firstand second lens arrays to move; and a power supply being electricallyconnected to the electrostrictive member to provide the electric currentto the electrostrictive member.
 14. The lens module of claim 13, whereinthe electrostrictive member has a plurality of through holes definedtherein, a central axis of each through hole being aligned with opticalaxes of the respective first lens and second lens.
 15. The lens moduleof claim 13, wherein the artificial muscle material is selected from agroup consisting of ferroelectric polymers and dielectric elastomers.